Add notmuch_database_set_timestamp and notmuch_database_get_timestamp

[notmuch] / notmuch.h

diff --git a/notmuch.h b/notmuch.h
index 912cbd2660af90d6f636b07f2acfd3d4ed8f3757..2c290fda85c8c6e97e2459b20ecfec46fa2b9058 100644 (file)
--- a/notmuch.h
+++ b/notmuch.h
@@ -31,6 +31,8 @@
 
 NOTMUCH_BEGIN_DECLS
 
+#include <time.h>
+
 #ifndef FALSE
 #define FALSE 0
 #endif
@@ -55,6 +57,10 @@ typedef int notmuch_bool_t;
  *
  * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
  *
+ * NOTMUCH_STATUS_FILE_ERROR: An error occurred trying to read or
+ *     write to a file (this could be file not found, permission
+ *     denied, etc.)
+ *
  * NOTMUCH_STATUS_FILE_NOT_EMAIL: A file was presented that doesn't
  *     appear to be an email message.
  *
@@ -69,6 +75,7 @@ typedef int notmuch_bool_t;
 typedef enum _notmuch_status {
     NOTMUCH_STATUS_SUCCESS = 0,
     NOTMUCH_STATUS_XAPIAN_EXCEPTION,
+    NOTMUCH_STATUS_FILE_ERROR,
     NOTMUCH_STATUS_FILE_NOT_EMAIL,
     NOTMUCH_STATUS_NULL_POINTER,
     NOTMUCH_STATUS_TAG_TOO_LONG,
@@ -167,6 +174,57 @@ notmuch_database_default_path (void);
 const char *
 notmuch_database_get_path (notmuch_database_t *database);
 
+/* Store a timestamp within the database.
+ *
+ * The Notmuch database will not interpret this key nor the timestamp
+ * values at all. It will merely store them together and return the
+ * timestamp when notmuch_database_get_timestamp is called with the
+ * same value for 'key'.
+ *
+ * The intention is for the caller to use the timestamp to allow
+ * efficient identification of new messages to be added to the
+ * database. The recommended usage is as follows:
+ *
+ *   o Read the mtime of a directory from the filesystem
+ *
+ *   o Call add_message for all mail files in the directory
+ *
+ *   o Call notmuch_database_set_timestamp with the path of the
+ *     directory as 'key' and the originally read mtime as 'value'.
+ *
+ * Then, when wanting to check for updates to the directory in the
+ * future, the client can call notmuch_database_get_timestamp and know
+ * that it only needs to add files if the mtime of the directory and
+ * files are newer than the stored timestamp.
+ *
+ * Note: The notmuch_database_get_timestamp function does not allow
+ * the caller to distinguish a timestamp of 0 from a non-existent
+ * timestamp. So don't store a timestamp of 0 unless you are
+ * comfortable with that.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Timestamp successfully stored in database.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception
+ *     occurred. Timestamp not stored.
+ */
+notmuch_status_t
+notmuch_database_set_timestamp (notmuch_database_t *database,
+                               const char *key, time_t timestamp);
+
+/* Retrieve a timestamp from the database.
+ *
+ * Returns the timestamp value previously stored by calling
+ * notmuch_database_set_timestamp with the same value for 'key'.
+ *
+ * Returns 0 if no timestamp is stored for 'key' or if any error
+ * occurred querying the database.
+ */
+time_t
+notmuch_database_get_timestamp (notmuch_database_t *database,
+                               const char *key);
+
 /* Add a new message to the given notmuch database.
  *
  * Here,'filename' should be a path relative to the the path of
@@ -180,6 +238,10 @@ notmuch_database_get_path (notmuch_database_t *database);
  *
  * NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
  *
+ * NOTMUCH_STATUS_FILE_ERROR: an error occurred trying to open the
+ *     file, (such as permission denied, or file not found,
+ *     etc.). Nothing added to the database.
+ *
  * NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
  *     like an email message. Nothing added to the database.
  */
@@ -329,10 +391,21 @@ notmuch_results_destroy (notmuch_results_t *results);
  * modified by the caller and will only be valid for as long as the
  * message is valid, (which is until the query from which it derived
  * is destroyed).
+ *
+ * This function will not return NULL since Notmuch ensures that every
+ * message has a unique message ID, (Notmuch will generate an ID for a
+ * message if the original file does not contain one).
  */
 const char *
 notmuch_message_get_message_id (notmuch_message_t *message);
 
+/* Get this filename for the email corresponding to 'message'.
+ *
+ * The returned filename is relative to the base of the database from
+ * which 'message' was obtained. See notmuch_database_get_path() .*/
+const char *
+notmuch_message_get_filename (notmuch_message_t *message);
+
 /* Get the tags for 'message', returning a notmuch_tags_t object which
  * can be used to iterate over all tags.
  *